isci: remove base_phy abstraction

Merge struct sci_base_phy into scic_sds_phy.  Until now sci_base_phy was
referenced using scic_sds_phy->parent field.

'sci_base_phy' state machine handlers were also merged into scic_sds_phy
state handlers.

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Maciej Trela <Maciej.Trela@intel.com>
Signed-off-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>